| 摘要 |
PURPOSE:To obtain the titled transparent and uniform resin solution of excellent storage stability, by reacting a tetracarboxylic acid with an aromatic diamine under specified conditions, aging the reaction mixture and post-polymerizing it. CONSTITUTION:A tetracarboxylic acid component based on substantially equimolar amounts of (A) 3,3'- and 4,4'-benzophenonetetracarboxylic acids is pre- reacted with (B) an aromatic diamine based on 4,4'-diaminodiphenyl ether at 100-200 deg.C in the presence of a halogenated phenol compound having a m.p. <=100 deg.C and a b.p. <=300 deg.C (e.g., p-chlorophenol) as a solvent to a specific reduced viscosity >=0.1, while the water of condensation is being removed with zeolite. Next, water in an amount of 0.1-5wt%, based on the total components A and B is added to the reaction system, and the mixture is aged at 80 deg.C or below for at least one hr during which time to water of condensation is being removed form the system. This mixture is postpolymerized at 100-200 deg.C and atmospheric pressure under reflux of water to a degree of imidation >=90% to obtain the titled resin solution of a concentration <=30wt%.
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